We report on ongoing experiments and simulations which model the performance of hole- coupled resonators. We have previously studied a hole-coupled resonator which was well inside the stable region (stability parameter g equals 0.8). In the far field, good agreement between experiment and simulation was obtained for both the intra-cavity and outcoupled mode-profile. The present study involves a resonator with a stability parameter of -0.987, identical to the stability parameter of the proposed Infrared Free Electron Laser (IRFEL) at Lawrence Berkeley Laboratory. The experiments were carried out with a frequency stabilized CW-HeNe laser beam at a wavelength of 632.8 nm. Both intra-cavity and outcoupled mode profiles and power levels were measured. The simulations were done using the code HOLD, which is based on the Fresnel approximation for the Huygens kernel. Within the experimental uncertainties, magnified due to the 1/(1+g) dependence of the mode characteristics on errors in measured resonator parameters, we have obtained fair agreement between experiment and simulation.